The association of marijuana use with outcome of pregnancy.

We analyzed interview and medical record data of 12,424 women to evaluate the relationship between marijuana usage and adverse outcomes of pregnancy. Low birthweight, short gestation, and major malformations occurred more often among offspring of marijuana users. When we used logistic regression to control for demographic characteristics, habits, and medical history data, these relationships were not statistically significant. The odds ratio for the occurrence of major malformations among marijuana users was 1.36, higher than odds ratios for other exogenous variables, and the 95 per cent confidence interval was 0.97-1.91. More data are needed to establish firmly or rule out an association between marijuana usage and major malformations. Until more information is available, women should be advised not to use marijuana during pregnancy.